It is known that increased nasal air resistance results from the application of heat and cold to regions of the face that receive sensory innervation from the maxillary branch of the fifth cranial nerve. The oral mucosa receives sensory innervation from this same nerve. Practically nothing is known concerning the effects upon nasal air resistance of heat, cold, or manipulative stimuli applied to the oral mucosa. Preliminary studies using a posterior rhinometric technique indicate that the application of either heat or cold to the human oral mucosa is associated with a significant increase in nasal air resistance. Data pertaining to these effects would be of significant value in assessing the probable adequacy of ventilation for dental patients with respiratory tract pathologies (such as rhinitus and emphysema) who must depend upon nasal ventilation. It is proposed to conduct a systematic, prospective study of the effects of thermal and sensory stimuli of the oral mucosa upon the upper airway resistance of humans. These studies will then be extended to include the effects of dental operative procedures upon nasal resistance.